A veterinarian has five feline patients that need to lose weight. She gives the cats five different brands of food in the same amount and weighs them every week for two months to see if any of the brands are more effective for losing weight. Given this situation, which statement is true?

• a.)The brand of cat food and change in cat weight are both response variables.
• b.)The brand of cat food is a response variable, while the change in cat weight is an explanatory variable.
• c.)The brand of cat food is an explanatory variable, while the change in cat weight is a response variable.
• d.)The brand of cat food and change in cat weight are both explanatory variables.